Geo-accumulation index and contamination factors of heavy metals (Zn and Pb) in urban river sediment

Abstract

The aim of the present study was to appraise the levels of heavy metal contamination (Zn and Pb) in sediment of the Langat River (Selangor, Malaysia). Samples were collected randomly from 15 sampling stations located along the Langat River. The parameters measured were pH, redox potential, salinity, electrical conductivity, loss of ignition, cation exchanges capacity (Na, Mg, Ca, K), and metal ions (Zn and Pb). The geo-accumulation index (I ) and contamination factor (C) were applied to determine and classify the magnitude of heavy metal pollution in this urban river sediment. Results revealed that the I of Pb indicated unpolluted to moderately polluted sediment at most of the sampling stations, whereas Zn was considered to be within background concentration. The I results were refined by the C values, which showed Pb with very high C at 12 stations. Zinc, on the other hand, had low to moderate C values. These findings indicated that the sediment of the Langat River is severely polluted with Pb. The Zn concentration at most sampling points was well below most sediment quality guidelines. However, 40% of the sampling points were found to have a Pb concentration higher than the consensus-based probable effect concentration of 128 mg/kg (concentrations above this value are likely to cause harmful effects). This result not only highlights the severity of Pb pollution in the sediment of the Langat River, but also the potential risk it poses to the environment.

Palaeotoxicity: reconstructing the risk of multiple sedimentary pollutants to freshwater organisms

“…Lake sediment records have been widely used to determine temporal trends of a broad range of pollutants including trace metals (Boyle et al 1998 ; Yang et al 2002 , 2010 ); persistent organic pollutants (Rose et al 2001 ; Yang et al 2016 ), pharmaceuticals (Kerrigan et al 2018 ) and fly-ash particles (Rose et al 2012 ; Rose 2015 ). However, despite a number of approaches employed to determine the effects of sediment contaminant mixtures to aquatic biota (for example Probable Effects Concentration Quotients (PEC-Qs), Ingersoll et al 2001 ; toxicity units (TUs), Lahr et al 2003 ; Hazard Quotients (HQs), Feng et al 2011 ; geoaccumulation indices (I geo ), Haris et al 2017 ), these have mainly been applied to surface sediments. Only rarely have these techniques been used with lake sediment records to determine historic toxic effects, even though this would allow contemporary status to be placed in an historical perspective such that directions of change (deterioration; improvement) could be determined as well as, perhaps more importantly, rates of change.…”

Contamination of small urban watercourses on the example of a stream in Krakow (Poland)

“…The chemical composition of stream waters can be affected in various ways by elements occurring in bottom sediments. Some minerals may help stabilize the composition of stream water due to their buffering capacity and others may cause precipitation of dissolved ions (Haris et al 2017). What's more, sediment acts as a metal reservoir and constitutes a sensible indicator of the background pollution of the watercourse (Shafie et al 2014).…”

Estimation of pollution indices and hazard evaluation from trace elements concentration in coastal sediments of Kerala, Southwest Coast of India

“…where Cx is the concentration of metal x in the sediment sample and Bx is the background or reference value of metal x. In order to compensate for the variations due to the lithogenic effects, a 1.5 background matrix factor is used (Haris et al 2017). The classification of geo-accumulation index is given in Table 4.…”